Superconductivity - Part 12: Matrix to superconductor volume ratio measurement - Copper to non-copper volume ratio of Nb3Sn composite superconducting wires

This part of IEC 61788 describes a test method for determining the copper to non-copper volume ratio of Cu/Nb3Sn wires. The test method given hereunder is applicable to Nb3Sn composite superconducting wires with a cross-sectional area of 0,1 mm2 to 3,0 mm2 and a copper to non-copper volume ratio of 0,1 or more. It does not make any reference to the filament diameter; however, it is not applicable to those superconducting wires with their filament, Sn, Cu-Sn alloy, barrier material and other non-copper portions dispersed in the copper matrix or those with the stabilizer dispersed. Furthermore, the copper to non-copper volume ratio can be determined on specimens before or after the Nb3Sn formation heat treatment process. The Cu/Nb3Sn wire has a monolithic structure with a round or rectangular cross-section. Though uncertainty increases, this method may be applicable to the measurement of the copper to non-copper volume ratio of the Cu/Nb3Sn wires whose cross-section and copper to non-copper volume ratio fall outside the specified ranges. This test method may be applied to other composite superconducting wires after some appropriate modifications.

Supraleitfähigkeit - Teil 12: Messung des Verhältnisses von Matrixvolumen zu Supraleitervolumen – Verhältnis des Kupfervolumens zum kupferfreien Volumen von Nb3Sn-Verbundsupraleiterdrähten

Supraconductivité - Partie 12 : Mesure du rapport volumique matrice/supraconducteur - Rapport volumique cuivre/non-cuivre des fils en composite supraconducteur Nb3Sn

La CEI 61788-12:2013 décrit une méthode d'essai de détermination du rapport volumique cuivre/non-cuivre des fils Cu/Nb3Sn. La méthode d'essai donnée dans la présente norme est applicable aux fils en composite supraconducteur Nb3Sn d'une section de 0,1 mm2 à 3,0 mm2 et d'un rapport volumique cuivre/non-cuivre d'au moins 0,1. Elle ne fait aucunement référence au diamètre du filament; cependant, elle n'est pas applicable aux fils supraconducteurs dont le filament, Sn, alliage Cu-Sn, la barrière métallique et autres parties qui ne sont pas en cuivre sont dispersés dans la matrice en cuivre, ainsi qu'aux fils dont le matériau stabilisateur est dispersé. En outre, le rapport volumique cuivre/non-cuivre peut être déterminé sur des éprouvettes avant ou après le processus de traitement thermique de formation du Nb3Sn. Le fil Cu/Nb3Sn a une structure monolithique avec une section ronde ou rectangulaire. Bien que l'incertitude augmente, cette méthode peut être appliquée pour la mesure du rapport volumique cuivre/non-cuivre de fils Cu/Nb3Sn dont la section et le rapport volumique cuivre/non-cuivre ne s'inscrivent pas dans les plages spécifiées ci-dessus. Il est admis d'appliquer cette méthode d'essai à d'autres fils en composite supraconducteur après y avoir apporté certaines modifications appropriées. Cette deuxième édition annule et remplace la première édition parue en 2002, dont elle constitue une révision technique. La principale révision est l'ajout de deux nouvelles annexes, 'Considérations relatives à l'incertitude' et 'Evaluation de l'incertitude de la méthode d'essai du rapport volumique cuivre/non-cuivre des fils en composite supraconducteur Nb3Sn'.

Superprevodnost - 12. del: Matrika za merjenje superprevodniškega volumenskega razmerja - Razmerje med bakrom in nebakrenim volumenskim razmerjem superprevodnih žic iz kompozita Nb3Sn

Ta del standarda IEC 61788 opisuje preskusno metodo za določanje razmerja med bakrom in nebakrenim volumenskim razmerjem žic iz Cu/Nb3Sn. Ta preskusna metoda se uporablja za superprevodne žice iz kompozita Nb3Sn s površino prereza od 0,1 mm2 do 3,0 mm2 in razmerjem med bakrom in nebakrenim volumenskim razmerjem 0,1 ali več. Ne določa premera filamenta; vendar se ne uporablja za superprevodne žice s svojim filamentom, žice, ki imajo v bakreni matrici Sn, zlitine Cu-Sn, odporne materiale in druge nebakrene dele, ali žice s stabilizatorjem. Poleg tega se lahko razmerje med bakrom in nebakrenim volumenskim razmerjem ugotovi na vzorcih pred nastankom Nb3Sb ali po njem v procesu toplotne obdelave. Žica Cu/Nb3Sn ima monolitno strukturo z okroglim ali pravokotnim prerezom. Kljub večji negotovosti se ta metoda uporablja za merjenje razmerja med bakrom in nebakrenim volumenskim razmerjem v žicah Cu/Nb3Sn, pri katerih prerez ter razmerje med bakrom in nebakrenim volumenskim razmerjem ne spadata v ta okvir. Ta preskusna metoda se lahko z nekaterimi potrebnimi spremembami uporablja za druge superprevodne žice iz kompozita.

General Information

Status
Published
Publication Date
05-Dec-2013
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
25-Nov-2013
Due Date
30-Jan-2014
Completion Date
06-Dec-2013

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SLOVENSKI STANDARD
SIST EN 61788-12:2014
01-januar-2014
1DGRPHãþD
SIST EN 61788-12:2003
Superprevodnost - 12. del: Matrika za merjenje superprevodniškega volumenskega
razmerja - Razmerje med bakrom in nebakrenim volumenskim razmerjem
superprevodnih žic iz kompozita Nb3Sn
Superconductivity - Part 12: Matrix to superconductor volume ratio measurement -
Copper to non-copper volume ratio of Nb3Sn composite superconducting wires
Supraleitfähigkeit - Teil 12: Messung des Verhältnisses von Matrixvolumen zu
Supraleitervolumen – Verhältnis des Kupfervolumens zum kupferfreien Volumen von
Nb3Sn-Verbundsupraleiterdrähten

Supraconductivité - Partie 12 : Mesure du rapport volumique matrice/supraconducteur -

Rapport volumique cuivre/non-cuivre des fils en composite supraconducteur Nb3Sn
Ta slovenski standard je istoveten z: EN 61788-12:2013
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
29.050 Superprevodnost in prevodni Superconductivity and
materiali conducting materials
SIST EN 61788-12:2014 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 61788-12:2014
---------------------- Page: 2 ----------------------
SIST EN 61788-12:2014
EUROPEAN STANDARD
EN 61788-12
NORME EUROPÉENNE
October 2013
EUROPÄISCHE NORM
ICS 29.050 Supersedes EN 61788-12:2002
English version
Superconductivity -
Part 12: Matrix to superconductor volume ratio measurement -
Copper to non-copper volume ratio of Nb Sn composite
superconducting wires
(IEC 61788-12:2013)
Supraconductivité - Supraleitfähigkeit -
Partie 12 : Mesure du rapport volumique Teil 12: Messung des Verhältnisses von
matrice/supraconducteur - Matrixvolumen zu Supraleitervolumen -
Rapport volumique cuivre/non-cuivre des Verhältnis des Kupfervolumens
fils en composite supraconducteur Nb Sn zum kupferfreien Volumen
(CEI 61788-12:2013) von Nb Sn-Verbundsupraleiterdrähten
(IEC 61788-12:2013)

This European Standard was approved by CENELEC on 2013-07-17. CENELEC members are bound to comply

with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard

the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on

application to the CEN-CENELEC Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CENELEC member into its own language and notified

to the CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,

the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,

Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,

Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 61788-12:2013 E
---------------------- Page: 3 ----------------------
SIST EN 61788-12:2014
EN 61788-12:2013 - 2 -
Foreword

The text of document 90/322/FDIS, future edition 2 of IEC 61788-12, prepared by IEC/TC 90

"Superconductivity" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as

EN 61788-12:2013.
The following dates are fixed:
(dop) 2014-04-17
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2016-07-17
standards conflicting with the
document have to be withdrawn
This document supersedes EN 61788-12:2002.

EN 61788-12:2013 includes the following significant technical changes with respect to

EN 61788-12:2002:

The main revision is the addition of two new annexes, "Uncertainty considerations" (Annex H) and

"Uncertainty evaluation in the test method of the copper to non-copper volume ratio of Nb Sn

composite superconducting wires" (Annex I).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such

patent rights.
Endorsement notice

The text of the International Standard IEC 61788-12:2013 was approved by CENELEC as a European

Standard without any modification.
---------------------- Page: 4 ----------------------
SIST EN 61788-12:2014
- 3 - EN 61788-12:2013
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD

applies.
Publication Year Title EN/HD Year
IEC 60050 Series International Electrotechnical Vocabulary - -
(IEV)
IEC 61788-5 - Superconductivity - EN 61788-5 -
Part 5: Matrix to superconductor volume ratio
measurement - Copper to superconductor
volume ratio of Cu/Nb-Ti composite
superconductors
---------------------- Page: 5 ----------------------
SIST EN 61788-12:2014
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SIST EN 61788-12:2014
IEC 61788-12
Edition 2.0 2013-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Superconductivity –
Part 12: Matrix to superconductor volume ratio measurement – Copper to non-
copper volume ratio of Nb Sn composite superconducting wires
Supraconductivité –
Partie 12: Mesure du rapport volumique matrice/supraconducteur –
Rapport volumique cuivre/non-cuivre des fils en composite supraconducteur
Nb Sn
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 29.050 ISBN 978-2-83220-864-9

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 7 ----------------------
SIST EN 61788-12:2014
– 2 – 61788-12 © IEC:2013
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope ............................................................................................................................... 7

2 Normative references ....................................................................................................... 7

3 Terms and definitions ....................................................................................................... 7

4 Principle ........................................................................................................................... 8

5 Apparatus ......................................................................................................................... 8

6 Measurement procedure ................................................................................................... 8

6.1 Preparation of specimen .......................................................................................... 8

6.1.1 General ....................................................................................................... 8

6.1.2 Procedures .................................................................................................. 8

6.2 Measurement .......................................................................................................... 9

6.2.1 Photo of cross-section ................................................................................. 9

6.2.2 Transfer ....................................................................................................... 9

6.2.3 Cutting......................................................................................................... 9

6.2.4 Measurement of paper mass ........................................................................ 9

6.3 Test procedure for the second specimen ................................................................. 9

6.4 Paper mass ............................................................................................................. 9

7 Calculation of results ........................................................................................................ 9

8 Uncertainty of the test method ........................................................................................ 10

9 Test report ...................................................................................................................... 10

9.1 Copper to non-copper volume ratio ........................................................................ 10

9.2 Identification of test specimen ............................................................................... 10

Annex A (normative) Measurement – Image processing method ......................................... 11

Annex B (normative) Measurement – Copper mass method ................................................ 12

Annex C (normative) Measurement method using planimeter .............................................. 13

Annex D (informative) Specimen polishing method ............................................................. 14

Annex E (informative) Difference of the copper to non-copper volume ratio before and

after the Nb Sn generation heat treatment process .............................................................. 15

Annex F (informative) Paper mass bias at copy .................................................................. 16

Annex G (informative) Cross-sections of Cu/Nb Sn wires ................................................... 17

Annex H (informative) Uncertainty considerations ............................................................... 18

Annex I (informative) Uncertainty evaluation in the test method of the copper to

non-copper volume ratio of Nb Sn composite superconducting wires.................................... 23

Figure G.1 – Cross-sections of four Cu/Nb Sn wire types according to the layout of the

stabilizer ............................................................................................................................... 17

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SIST EN 61788-12:2014
61788-12 © IEC:2013 – 3 –

Table H.1 – Output signals from two nominally identical extensometers ................................ 19

Table H.2 – Mean values of two output signals ..................................................................... 19

Table H.3 – Experimental standard deviations of two output signals ..................................... 19

Table H.4 – Standard uncertainties of two output signals ...................................................... 20

Table H.5 – Coefficient of variations of two output signals .................................................... 20

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SIST EN 61788-12:2014
– 4 – 61788-12 © IEC:2013
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SUPERCONDUCTIVITY –
Part 12: Matrix to superconductor volume ratio measurement – Copper to
non-copper volume ratio of Nb Sncomposite superconducting wires
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in

addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,

Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their

preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with

may participate in this preparatory work. International, governmental and non-governmental organizations liaising

with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for

Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence between

any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses

arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 61788-12 has been prepared by IEC technical committee 90:

Superconductivity.

This second edition cancels and replaces the first edition published in 2002. It constitutes a

technical revision. The main revision is the addition of two new annexes, "Uncertainty

considerations" (Annex H) and "Uncertainty evaluation in the test method of the copper to

non-copper volume ratio of Nb Sn composite superconducting wires" (Annex I).
The text of this standard is based on the following documents:
FDIS Report on voting
90/322/FDIS 90/325/RVD

Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

---------------------- Page: 10 ----------------------
SIST EN 61788-12:2014
61788-12 © IEC:2013 – 5 –

A list of all parts of the IEC 61788 series, published under the general title Superconductivity,

can be found on the IEC website.

The committee has decided that the contents of this publication will remain unchanged until the

stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to

the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The “colour inside” logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct understanding

of its contents. Users should therefore print this publication using a colour printer.

---------------------- Page: 11 ----------------------
SIST EN 61788-12:2014
– 6 – 61788-12 © IEC:2013
INTRODUCTION

The copper to non-copper volume ratio of superconducting wires serves as an important

numeric value used when determining the critical current density and its stability, which are two

of the important characteristics of superconducting wires. This standard is concerned with the

standardization of the test method for the copper to non-copper volume ratio of copper stabilized

Nb Sn multi-filamentary composite superconducting wires (hereinafter referred to as Cu/Nb Sn

3 3
wires).

Cu/Nb Sn wires can be classified into four types according to the layout of the stabilizer as

shown in Annex G: the external stabilizer type, the internal stabilizer type, the distributed

stabilizer type and the contiguous stabilizer with distributed barrier type. The test method

specified by this standard may be applicable to a type whose cross-section is of the external

stabilizer or the internal stabilizer type regardless of the production process employed.

With regard to the internal stabilizer type, the internal structure of some Cu/Nb Sn wires

prevents copper from being dissolved and removed. This precludes the application of the copper

mass method, unlike with copper matrix Nb-Ti superconducting wires. New methods are

therefore needed, as detailed in the following:

• the paper mass method, where a photo of the cross-section of the wire being measured is

traced onto tracing paper, or a copy is made of the photo using a copying machine; the paper

is then cut out into different portions to measure the mass of each piece of paper;

• the image processing method, where the image of the photo of the cross-section is digitized

and the areas are analyzed with software;

• the copper mass method, where the copper of the specimen is dissolved in nitric acid

solution to leave only the non-copper portion, and to measure the mass of the specimen and

the non-copper portion of specimen.

This standard is concerned with the paper mass method which is adopted more generally. As

supplementary methods, the image processing method and the copper mass method adopted

for Cu/Nb Sn wires are specified in Annex A and Annex B, respectively. The method using a

planimeter is specified in Annex C. In Annex D an example of a polishing method is also

specified.
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SIST EN 61788-12:2014
61788-12 © IEC:2013 – 7 –
SUPERCONDUCTIVITY –
Part 12: Matrix to superconductor volume ratio measurement – Copper to
non-copper volume ratio of Nb Sn composite superconducting wires
1 Scope

This part of IEC 61788 describes a test method for determining the copper to non-copper volume

ratio of Cu/Nb Sn wires.

The test method given hereunder is applicable to Nb Sn composite superconducting wires with

2 2

a cross-sectional area of 0,1 mm to 3,0 mm and a copper to non-copper volume ratio of 0,1 or

more. It does not make any reference to the filament diameter; however, it is not applicable to

those superconducting wires with their filament, Sn, Cu-Sn alloy, barrier material and other

non-copper portions dispersed in the copper matrix or those with the stabilizer dispersed.

Furthermore, the copper to non-copper volume ratio can be determined on specimens before or

after the Nb Sn formation heat treatment process.

The Cu/Nb Sn wire has a monolithic structure with a round or rectangular cross-section.

Though uncertainty increases, this method may be applicable to the measurement of the copper

to non-copper volume ratio of the Cu/Nb Sn wires whose cross-section and copper to

non-copper volume ratio fall outside the specified ranges.

This test method may be applied to other composite superconducting wires after some

appropriate modifications.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and

are indispensable for its application. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments)

applies.
IEC 60050 (all parts), International Electrotechnical Vocabulary (available at

IEC 61788-5, Superconductivity – Part 5: Matrix to superconductor volume ratio measurement –

Copper to superconductor volume ratio of Cu/Nb-Ti composite superconductors
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60050-815 as well as

the following apply.
3.1
copper to non-copper volume ratio

ratio of the volume of the copper stabilizing material to the volume without copper consisting of

Cu/Nb Sn wires
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SIST EN 61788-12:2014
– 8 – 61788-12 © IEC:2013
4 Principle

The principle of this method is described in the following. A photo of the polished cross-section

of the sample wire shall be taken with a metallograph. This photo is traced onto tracing paper, or

a copy is made of the photo using a copy machine. The tracing paper or copy is then cut out into

different portions to measure the mass of each piece of paper. The copper to non-copper volume

ratio can be obtained from the ratio of the paper mass of both portions.
5 Apparatus
The apparatus required for the test includes the following:
• metallograph;
• photomicrographic camera;
• polishing machine;
• balance;

A balance shall have a manufacturer’s specified uncertainty of ±0,1 mg or better.

• scissors or cutter.
6 Measurement procedure
6.1 Preparation of specimen
6.1.1 General

The specimen shall be prepared from a Cu/Nb Sn wire before or after the Nb Sn generation

3 3

heat treatment process. Two specimens shall be cut out of a Cu/Nb Sn wire being measured.

NOTE In the case of measuring an internal tin processed wire before the treatment, the stabilizer copper is carefully

distinguished from copper in other parts.
6.1.2 Procedures
6.1.2.1 Mold

The two specimens shall be molded at the same time for polishing. As the molding material, an

appropriate resin shall be used to embed the specimen for observation through the metallograph.

When molding, it shall be carefully checked that the cross-section of the specimen is at right

angles to the polishing surface as much as possible.
6.1.2.2 Polishing

The specimen shall be polished using emery paper and buffed using an abrasive material. A

microscope shall be used to check that the polished surface is smooth enough to ensure good

photographing, especially the boundary between the copper and non-copper portions and the

periphery of the sample. The surface shall be re-polished, if these areas are not clear because

of abrasive scratches. An example of the polishing method is specified in Annex D.

6.1.2.3 Cleaning and drying

The polished specimen shall be cleaned using running water, distilled water, acetone or ethyl

alcohol. It shall be checked that the cleaning agent does not dissolve the resin in which the

specimen is embedded. An ultrasonic cleaning machine may be used if necessary. After

cleaning, the specimen shall be dried with chilled or hot air to prevent the polished surface from

oxidizing or discoloring.
---------------------- Page: 14 ----------------------
SIST EN 61788-12:2014
61788-12 © IEC:2013 – 9 –
6.2 Measurement
6.2.1 Photo of cross-section

A black-and-white or color picture of the cross-section shall be taken using the metallograph.

The magnification shall be selected for the entire cross-section of the specimen to fit within the

size of the photo. A photomicrographic camera with as much depth of focus as possible shall be

used, so that the boundary between copper and non-copper portions and the periphery of the

specimen appear clear and vivid on the photo.
6.2.2 Transfer

The image of the cross-section shall be traced on tracing paper so that the copper portion and

non-copper portion can be separated.

As an alternative method, a copy of the photo of the cross-section shall be made using a copying

machine. A zoom ratio of the copier that will fit the image in a sheet of paper and allow the cutting

work to be done easily shall be selected. If a copy is to be made using a copy machine, a copy

of a scale shall be made at the same time, to check that the copier distortion is within ±1 % (see

Annex F).
6.2.3 Cutting

Scissors or a cutter shall be used to cut the tracing paper or the copy into the copper and

non-copper portions.
6.2.4 Measurement of paper mass
The first specimen shall be measured twice.

The paper mass of the copper portion and non-copper portion shall be measured with a

combined standard uncertainty not to exceed 0,1 mg. Each portion shall be measured twice and

the average of the two measurements shall be reported.

During the measurement, caution shall be taken to ensure that the measurement is not affected

by humidity. If the mass continues to change, the specimen shall remain in the measurement

chamber for about 10 min before resuming the measurement sequence.
6.3 Test procedure for the second specimen

The steps given under 6.2 shall be repeated to measure the paper mass for the second

specimen.
6.4 Paper mass
) to that of the non-copper portion (M ) shall be
The paper mass of the copper portion (M
Cu non
obtained by averaging the paper mass measured at steps 6.2 and 6.3.
7 Calculation of results

For each measurement taken in 6.2 and 6.3, the copper to non-copper volume ratio shall be

obtained from the ratio of the paper mass of the copper portion to that of the non-copper portion.

Copper to non-copper volume ratio is expressed as M /M
Cu non
The ratio shall be rounded to two decimal places.
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SIST EN 61788-12:2014
– 10 – 61788-12 © IEC:2013
8 Uncertainty of the test method

The uncertainty of this test method is affected by the sag of the specimen occurring from

polishing, transfer to tracing paper, distortion of the copying machine and uncertainty in cutting

out portions from the paper. The relative combined standard uncertainty of this method shall not

exceed 2,5 %(using a coverage factor of k = 1) as shown in Clause I.1.
9 Test report
9.1 Copper to non-copper volume ratio
The report shall contain the following information:
a) copper to non-copper volume ratio of each specimen;
b) wire diameter or size of the cross-section if it is a rectangular shape;

c) whether the specimens had or had not received the Nb Sn generation heat treatment.

The report shall contain the following information if known:
d) manufacturing method;
e) configuration of the copper matrix;
f) photo of cross-section;
g) measurement conditions and information;
h) raw measured data;
i) information of measurement equipment.
9.2 Identification of test specimen
The test specimen shall be identified by the following information if known:
a) name of the manufacturer of the specimen;
b) identification number;
c) billet number.
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SIST EN 61788-12:2014
61788-12 © IEC:2013 – 11 –
Annex A
(normative)
Measurement – Image processing method
A.1 Method

The following details describe the method that can be used to digitize the image on the

cross-sectional photo (image processing method).

a) Following the steps from 6.1 through 6.2.1, photos of the cross-section of the specimens

shall be taken.

b) Using a scanner, the image of the cross-section photos shall be captured in a personal

computer.

c) Using image analysis software, the number of pixels on the copper portion and non-copper

portion shall be determined.

d) The copper to non-copper volume ratio of the specimen shall be determined using the

following equation:
R =
Cu,i
non
(A.1)
where
R is the copper to non-copper volume ratio with image processing method;
Cu,i
N is the number of pixels on the copper portion;
N is the number of pixels on the non-copper portion.
non
A.2 Test report

The following information shall be reported in addition to the data listed in Clause 9: image

analysis software used.

NOTE 1 Measurement uncertainty of the image processing method is determined by the quality of image of the photo

of cross-section. What is necessary
...

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